Question

I’m developing an iPhone application where I have a bunch of images bundled with the app and also new images being downloaded and put in Documents dir. When I need them I don’t know if they are new or bundled so I made a simple helper class that checks it for me.

It works, but it’s slow. How can I speed it up? I know I need to cache the images that comes from Documents dir, but what would be the most effective way? The code is currently in no way optimized. Any help is appriciated, thanks.

http://pastebin.com/L7WCqjxX

Answer 1

Some hints:

• Not always search for your docsDir (NSSearchPathForDirectoriesInDomains), store it in a instance variable (or if class method [like your case], store it in a static variable)
• make it “threaded”
  • run your methode in background and create a delegate protocol for sending to your view controller (or other delegated class). Call + (UIImage *)imageNamed:(NSString *)name in a background thread. When the images is loaded from NSData/Path, then inform your ViewController (performSelectorOnMainThread!) that the images was loaded in background and present then the image (this will avoid jerks massively).
• consider to use NSOperationQueue to get the full power of multicore processors!

Take a look at SDWebImage… they to all the stuff i told you above.